JavaScript Variables and Data Types Worksheet

Question 1

Find a reference that lists all the keywords in the JavaScript programming language.

"Reserved" Words Here

Question 2

True or false: keywords and variable names are NOT case sensitive.

False. Keywords and variables are case sensitive

Question 3

There are some rules for how you can name variables in JavaScript. What are they?

Variable must start with a letter
the Variable will break apart upon using a space character (no spaces!)
camelCasing is a good convention to follow in the field of programming

Question 4

What is 'camelCase'?

If i named a variable 'Kind of pizza customer chose', the camel casing would look something like this:
kindOfPizzaCustomerWants

Question 5

What are ALL the different data types in JavaScript (note that there are some that we did not discuss in class)?

String (text), number, boolean -- as well as Bigint(), Undefined, Null, Symbol and Object

Question 6

What is a boolean data type?

A boolean datatype is a binary true and false datapoint. Activation of one of the two could lead someone down an entirely different path of code.

Question 7

What happens if you forget to put quotes around a string when you initialize a variable to a string value? How does JavaScript try to interpret this?
For example: var lastName = Jones;

JavaScript will read that the 'lastName' variable is calling upon another variable 'Jones' for its value.

Question 8

What character is used to end a statement in JavaScript?

The semi-colon (;).

Question 9

If you declare a variable, but do not initialize it, what value will the variable store?

The variable will store a value of undefined

Question 10

What output will the following program produce? In other words, explain what you would see in the console log if you ran a program like this:


const firstTestScore = 98;
const secondTestScore = "88";
const sum = firstTestScore + secondTestScore;
console.log(sum);
console.log(typeof sum);

The console log would read "9888"; and the following line would read 'string'.

Question 11

What output will the following program produce? In other words, explain what you would see in the console log if you ran a program like this:


const total = 99;
console.log("total");
console.log(total);

The console log would read: total
99

Question 12

What is the difference between these two variables?


const score1 = 75;
const score2 = "75";

One is a variable with the data of a number,
the other variable has data as a string.

Question 13

Explain why the this code will cause the program to crash:


const score = 0;
score = prompt("Enter a score");

the variable "score" has been assigned an unchanging const behavior.
The console log will report an error reflecting this mistake.

Coding Problems

Coding Problems - See the 'script' element below this h1 element. You will have to write some JavaScript code in it.

Here are some tips to help you with the coding problems:

To do this assignment, you'll need to know how to open the brower's developer tools (press F12) and look at the console log.
Pay extremely close attention to syntax! One little syntax error can mess up your entire program.
After you complete each problem, refresh the page in the browser and look in the console your log message and for errors.
If you have an error in the console, check the line number of the error then look for syntax errors on that line (and the line before and the line after that line).
If you get stuck on this assignment, please ask for help! Dealing with syntax errors can be extremely frustrating for beginners. It takes a lot of effort and support to get comfortable with the syntax of a language. Don't be afraid to ask for help, your success in this class will depend on your willingness to get help!